Emergence of uniform linearly-arranged micro-droplets entrapping DNA and living cells through water/water phase-separation

Mayu Shono,Kenichi Yoshikawa,Ritsuki Ito,Hiroki Sakuta,Fumika Fujita

doi:10.1038/s41598-021-02990-w

Abstract

Living cells maintain their lives through self-organization in an environment crowded with a rich variety of biological species. Recently, it was found that micro-droplets containing biomacromolecules, which vary widely in size, are generated accompanied by water/water phase-separation by simple mechanical mixing of an aqueous solution with binary polymers. Here, we report that cell-sized droplets of nearly the same size are generated as a linear array within a glass capillary upon the introduction of a binary polymer solution of polyethylene glycol (PEG) and dextran (DEX). Interestingly, when DNA molecules are added to the polymer solution, stable droplets entrapping DNA molecules are obtained. Similarly, living cells are entrapped spontaneously for the linearly-arranged cell-sized droplets. This simple method for generating micro-droplets entrapping DNA and also living cells is expected to stimulate further study on the self-construction of protocells and micro organoids.

Highlights

Living cells maintain their lives through self-organization in an environment crowded with a rich variety of biological species
It has been shown that, in a similar polyethylene glycol (PEG)/dextran (DEX) solution, prion protein exhibits characteristic localization depending on the solution conditions[30]
It may be of scientific value to extend the discovery of the present study so as to explore the suitable experimental conditions, such as composition of the solution, size and hydrophilicity of the narrow channel, to obtain stable, uniform droplets

Summary

Introduction

Living cells maintain their lives through self-organization in an environment crowded with a rich variety of biological species. As a somewhat different research stream, aqueous two-phase systems (ATPS), or water/water (w/w) phase segregation, generated in the presence of a relatively crowded environment with a binary polymer solution have been studied in relation to the formation of protocells as well as artificial models of organelles[22,23,24,25,26]. It was revealed that, under suitable solution conditions containing phospholipid, cell-sized droplets covered by phospholipid and entrapping DNA molecules are generated in a self-organized m anner[31]. In these studies, the self-emergence of cell-like structures was confirmed, the size of the w/w droplets or protocells exhibits rather wide dispersion with a range of μm-mm, because the w/w droplets were generated after simple mechanical mixing. Effective entrapment of DNA and living cells in these arranged, uniformsized w/w droplets will be demonstrated

Methods

Results

Conclusion